
package org.apache.solr.search;

import org.apache.lucene.queries.function.FunctionQuery;
import org.apache.lucene.queries.function.ValueSource;
import org.apache.lucene.queries.function.valuesource.QueryValueSource;
import org.apache.lucene.queryparser.classic.ParseException;
import org.apache.lucene.search.*;
import org.apache.solr.common.params.SolrParams;
import org.apache.solr.common.util.NamedList;
import org.apache.solr.request.SolrQueryRequest;
import org.apache.solr.search.function.*;

/**
 * Create a range query over a function.
 * <br>Other parameters:
 * <br><code>l</code>, the lower bound, optional)
 * <br><code>u</code>, the upper bound, optional)
 * <br><code>incl</code>, include the lower bound: true/false, optional, default=true
 * <br><code>incu</code>, include the upper bound: true/false, optional, default=true
 * <br>Example: <code>{!frange l=1000 u=50000}myfield</code>
 * <br>Filter query example: <code>fq={!frange l=0 u=2.2}sum(user_ranking,editor_ranking)</code> 
 */
public class FunctionRangeQParserPlugin extends QParserPlugin {

    public static String NAME = "frange";

    @Override
    public void init(NamedList args) {
    }

    @Override
    public QParser createParser(String qstr, SolrParams localParams, SolrParams params, SolrQueryRequest req) {

        return new QParser(qstr, localParams, params, req) {
            ValueSource vs;
            String funcStr;

            @Override
            public Query parse() throws ParseException {
                funcStr = localParams.get(QueryParsing.V, null);
                Query funcQ = subQuery(funcStr, FunctionQParserPlugin.NAME).getQuery();
                if (funcQ instanceof FunctionQuery) {
                    vs = ((FunctionQuery) funcQ).getValueSource();
                } else {
                    vs = new QueryValueSource(funcQ, 0.0f);
                }

                String l = localParams.get("l");
                String u = localParams.get("u");
                boolean includeLower = localParams.getBool("incl", true);
                boolean includeUpper = localParams.getBool("incu", true);

                // TODO: add a score=val option to allow score to be the value
                ValueSourceRangeFilter rf = new ValueSourceRangeFilter(vs, l, u, includeLower, includeUpper);
                FunctionRangeQuery frq = new FunctionRangeQuery(rf);
                return frq;
            }
        };
    }
}
